Longitudinal adjustment device in a vehicle seat, especially for two-door motor vehicles

ABSTRACT

A longitudinal adjusting device on a motor vehicle seat having a seat back adjustable relative to the seat part and forwardly foldable after releasing an arresting device, has movable rails on which the seat is fastened. The moveable rails can slide in guide rails attached to the vehicle. One movable rail has a locking device that releasably locks the moveable rail on the guide rail. The locking device has a positioning device for returning the seat to its previous longitudinal position. The positioning device has a positioning disc with locking teeth and an arresting lever with a toothed segment engaging the locking teeth. The arresting lever can be released from the locking teeth to allow rotation of the positioning disc during longitudinal adjustment of the seat. A spring-loaded winding drum is arranged coaxially to the positioning disc and allows the seat part to slide forward by a tension member attached to the seat part or the guide rail.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention pertains to a longitudinal adjusting device for the seatof a motor vehicle, especially two-door motor vehicles, the back ofwhich seat can be tilted adjustably with respect to the seat part bymeans of adjusting hardware, and which, after the release of anarresting device, can be flipped forward, where the seat part isattached to movable rails which can slide along guide rails permanentlyattached to the vehicle, and where at least one movable rail has alocking device which can be disengaged from the guide rail, to whichlocking device a positioning device is assigned, which makes it possiblefor the seat to be returned to the original longitudinal positionselected for it, which positioning device comprises a positioning diskwith a set of external teeth, into which the toothed segment of anarresting lever engages, which lever is supported in a fixed positionwith respect to the movable rail but which can be moved out of the wayif needed, where, coaxial to the positioning disk, a spring-loadedwinding drum is mounted, by means of which the seat part can be shiftedforward by the intermediate action of a tension member permanentlyattached to the vehicle floor or to the guide rail, the winding drumbeing provided with a stop for limiting the extent to which it can berotated in the reverse direction by a counterstop on the positioningdisk.

2. Description of the Related Art

A longitudinal adjusting device of the type described above can bederived from DE 196-47,447, in which the locking device can be releasedin two different ways so that the seat can be shifted longitudinally.First, by lifting a release handle in the forward area under the seat,the locking device attached to the movable rail can be released via atransverse lever from the position in which it is connected to the guiderail; that is, the locking catches of the locking device are lifted outof the row of teeth on the guide rail against the force ofself-restoring springs. As this occurs, the end part of the releasehandle carries a connecting lever along with it in the releasedirection; this connecting lever lifts the toothed segment of anarresting lever out of the external teeth of a positioning disk. In thiscase, the previously selected terminal stop position used as a guide forreturning the seat to the originally selected position is lost. So thatthe vehicle seat can be shifted without losing the position of theterminal stop, the connecting lever is detached from the release leverby way of an unlocking lever supported on the movable rail, so that thearresting lever remains undisturbed; as a result, the locking positionof the positioning disk is pre-served. Nevertheless, the unlocking leversimultaneously presses the release handle against the transverse lever,so that this lever lifts the locking catches of the locking device outof the row of teeth on the guide rail. Thus, the previously selectedstop position remains preserved in the memory module, while the seatpart along with the forward-tipped back can be slid forward and backagain to the previously selected stop. To assist the forward slidingmovement of the seat, a previously mentioned winding drum is provided,which is spring-loaded in the direction of the forward sliding movement.This drum is connected by way of a tension member either to the floor ofthe vehicle in the forward area of the rail arrangement or to theforward end of the guide rail. The position of the stop used as a guidefor returning the seat to its originally selected longitudinal positioncan be adjusted when the seat is slid backwards by allowing the rotationof the winding drum, which carries another stop, to move the stop of thepositioning disk along until, upon completion of the rearward slidingmovement of the seat, the locking device holds the movable rail in afixed position on the guide rail. At this point, the pivoting of therelease handle back to its original position also causes the positioningdisk to be held by the arresting lever, so that the position which thestop on the positioning disk reached at that time is fixed. So that thewinding drum can now be allowed to make several revolutions without theneed to release the positioning disk, two check rings are insertedbetween the stop on the positioning disk and the stop on the windingdrum; these rings in turn have their own stops, which can be carriedalong in succession by the winding drum. Thus, while the seat is beingslid backwards, the stops on the check rings move the stop on thewinding drum into a stop position with respect to the stop of thepositioning disk, while the stop position of the positioning disk isbeing maintained. To ensure that the check rings function properly, theymust be installed in the correct order one behind the other; otherwise,it is impossible for the originally selected position of the seat to berestored. In addition, if it desired to allow the seat to slide a longdistance, the number of check rings arranged in a row must be increased.This requires a large amount of space in the width direction, and italso increases the cost.

SUMMARY OF THE INVENTION

The task of the invention is to improve a longitudinal adjusting deviceof the general type described above in such a way that, first, theabove-cited disadvantages can be avoided, and, second, that the numberof components, especially of the memory module, can be reduced. Thistask is accomplished by a link block, which is guided in a spiralconnecting link and which makes it possible for the winding drum torotate, being provided between the stop of the winding drum and thecounter stop of the positioning disk. As a result, check rings, such asthose used in the solution according to the state of the art describedabove, can be completely eliminated in the solution according to theinvention. Another advantage is that, depending on the design of thespiral connecting link and the link block, it is possible, if needed,for the winding drum to execute more than the approximately tworevolutions which can be achieved with the check rings known accordingto the state of the art, which means that the movable rails can be slidmuch farther along the guide rails.

A practical embodiment of the spiral connecting link and the link blockcan be achieved by designing the link block preferably as a ringsegment, which has a guide rib which engages with the spiral connectinglink. The connecting link takes the form of a groove recessed into thesidewall of the positioning disk. The spiral connecting link in thiscase is preferably designed so that it begins a short radial distancefrom the hub of the positioning disk and ends at the counterstop on thepositioning disk, located radially just below the locking teeth; thepitch of the spiral connecting link is such that the radially outwarddirected component of the link block's motion can carry it underneathand past the counterstop of the positioning disk before the block makesits last revolution.

The link block can be given precise radial guidance as the positioningdisk rotates by providing guide fingers on the link block, oneprojecting from each of the two end surfaces of the block, both pointingat the hub of the positioning disk. These guide fingers are arrangedwith respect to each other like a fork and project across the hub at atangent to its outer circumference. It is obvious that the guide fingersmust be long enough to remain in contact with the outside surface of thehub of the positioning disk even after the greatest possible radialdistance between the link block and the hub of the positioning disk hasbeen reached.

As previously mentioned, the counterstop is assigned to the positioningdisk, whereas the stop is assigned to the winding drum. The stop on thewinding drum can preferably be formed by the outsidewalls of aninsertion pocket for a lead retainer seal of the tension member.

So that the winding drum can be rotated freely with respect to thepositioning disk, the counterstop of the positioning disk projectsaxially only so far from its sidewall that the ribs and insertion pocketof the winding drum can be rotated freely past the counterstop. Theaxial length of the link block, furthermore, is greater than the axiallength of the counterstop, because, when the link block is restingagainst the counterstop of the positioning disk, it must also form anabutment for the stop of the winding drum.

BRIEF DESCRIPTION OF THE DRAWING

The invention is shown in the drawing on the basis of an exemplaryembodiment and is explained in greater detail below:

FIG. 1 shows a schematic diagram of a vehicle seat, seen from the side;

FIG. 2 shows a pair of rails of a vehicle seat arranged along one of thelong sides of a seat provided with the longitudinal adjusting device, ina side view looking from inside the seat;

FIG. 3 shows a plan view of the pair of rails seen in FIG. 1 with thelongitudinal seat adjusting device;

FIGS. 4a-4 c show the rear area of the manually actuated release handlein three different positions. The position according to FIG. 4a showsthe rest position; the position according to FIG. 4b shows how thelocking device is released when the back of the seat is pivoted forward;and FIG. 4c shows how the locking device and the positioning device arereleased by the pivoting of the release handle;

FIG. 5 shows the positioning device in a longitudinal cross sectionalong line V—V of FIG. 4a;

FIG. 6 shows the positioning device seen in FIG. 5 in a cross sectionalong line VI—VI of FIG. 5;

FIG. 7 shows the positioning device seen in FIG. 5 in a cross sectionalong line VII—VII of FIG. 5;

FIG. 8 shows the locking device and the pair of rails in a cross sectionalong line VIII—VIII of FIG. 2; and

FIG. 9 shows the longitudinal adjusting device comprising a positioningdevice together with a pair of rails in a perspective view lookingtoward the inside of the pair of rails.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The vehicle seat shown schematically in FIG. 1 consists of a seat part10 and a seat back 11, which is attached to the seat part by a hingemechanism (not shown), which allows the angle of the back to beadjusted. The back can also be flipped forward with respect to seat part10 around a pivot point 14 by pulling on a handle 13 connected to anarresting device 12. Each of the two longitudinal sides of seat part 10are connected along the bottom to a movable rail 15, which engages in aguide rail 16, both guide rails being attached permanently to the floorof the vehicle. Movable rail 15, as can be seen especially in FIG. 8, issupported on guide rail 16 by rolling elements 17, 18 to allow freedomof longitudinal movement. On its incurved bottom, guide rail 16 has alongitudinal row of openings (not labeled separately), spaced a certaindistance apart, which form a row of teeth. Into these openings, at leastone of several locking catches 20 engages, these catches beingcomponents of a locking device 19, mounted in a fixed position onmovable rail 15. The catches can be disengaged against the action ofsprings by a transverse lever 21, also mounted on movable rail 15; toaccomplish this, a release handle 22, also in a fixed position onmovable rail 15, is actuated. Locking device 19 of the longitudinal seatadjusting device, however, can also be released by handle 13 on seatback 11 together with arresting device 12 of the seat back, in that anunlocking lever 24 is actuated by way of a Bowden cable 23. Thisunlocking lever acts by way of an angled section 25 on release handle 22in the unlocking direction and thus also actuates transverse lever 21 insuch a way as to disengage locking catches 20 from the row of teeth inguide rail 16. The unlocking lever is supported by a pivot 26 on amounting plate 27, which is attached in turn to movable rail 15. Ahousing 28, consisting of a lower housing part 29 and an upper housingpart 30, which holds positioning device 31 and its winding drum 32,designed as a rotating element, is also attached to this mounting plate27.

Can-shaped upper housing part 30, which can be seen in FIG. 5, isconnected by way of clip projections 33 along the edges, which can alsobe seen in FIGS. 4a-4 c, to disk-shaped lower housing part 29, thislower housing part 29 being permanently connected in a manner not shownto mounting plate 27 attached to movable rail 15. An inward-projectingaxle 34 is provided in the center of cup-like upper housing part 30. Apositioning disk 35 is supported with freedom of rotation on this axle34; a set of locking teeth 36 extends around the entire outsidecircumference of the disk. On the side facing disk-shaped lower housingpart 29, positioning disk 35 has a recess, in which a spiral spring 37,functioning as a torsion spring, is held. The inner, angled, end of thisspring engages in a recess 38 in axle 34, whereas the outer end of thespring is held in a manner not shown in detail in the circumferentialarea of the recess in positioning disk 35.

Together with positioning disk 35, the previously mentioned winding drum32 is also supported on axle 34 so that it can rotate independently ofthe positioning disk. On the side facing away from positioning disk 35,winding drum 32 has a recess 39, which also holds a spiral spring 40,which functions as a torsion spring. In a manner known in itself, theinner end of this spring is attached to axle 34, whereas the outer endis attached to the outside lateral surface of winding drum 32. Theoutside lateral surface of winding drum 32 has a section 41 of reduceddiameter, which forms the holding space for a tension member 42, whichis attached to the winding drum and which can be in the form of a belt,for example. Underneath reduced-diameter section 41, there is aninsertion pocket 43, oriented toward the center of winding drum 32, inwhich a lead retainer seal 44, permanently attached to one end oftension member 42, fits. Each of the two outsidewalls of insertionpocket 43 extending in the axial direction forms a stop 45, the purposeof which will be described later. In addition to the walls of insertionpocket 43, which serve to increase the rigidity between the outsidelateral surface and the hub of winding drum 32 and also form stops 45,ribs 46 are also provided between the hub and the outside lateralsurface of winding drum 32. At the free end of tension member 42, alock-in-position piece 47 is provided, by means of which tension member42 is attached to guide rail 16, mounted in a fixed position on thefloor.

A hub 49 projects from sidewall 48 of positioning disk 35; this hubpoints toward winding drum 32 and surrounds axle 34. A short radialdistance away from this hub 49, a spiral connecting link 50 begins, andit ends at a counterstop 51, which projects from sidewall 48 ofpositioning disk 35 just below locking teeth 36. This counterstop 51does not project far enough in the axial direction from sidewall 48 ofpositioning disk 35 to prevent either the radially oriented boundarywalls of insertion pocket 43 or ribs 46 of winding drum 32 from rotatingfreely past counterstop 51. Spiral connecting link 50 is formed by agroove recessed into sidewall 48 of positioning disk 35. A guide rib 53of a link block 52 engages in the groove which forms spiral connectinglink 50. Link block 52, designed as a ring segment, forms anintermediate member between the associated stop 45 of winding drum 32and counterstop 51 of positioning disk 35. The axial dimension of thelink block is selected so that it can come to rest, first, against theassociated stop 45 of the winding drum and, second, against counterstop51 of positioning disk 35. To provide guidance, a guide finger 55projects out from each end 54 of link block 52. These guide fingers 55are arranged to form a fork, and even in the most extreme radialposition, they remain tangent to hub 49 of positioning disk 35 on bothsides.

Upper housing part 30 has on its circumferential area, adjacent todisk-shaped lower housing part 29, a cut-out section 56, through whichtoothed segment 58 of an arm of disengagable arresting lever 57 canpass, so that it can engage with locking teeth 36 of positioning disk35. This arresting lever 57 is able to pivot around a pivot 59 onmounting plate 27, and its toothed segment is held in engagement withlocking teeth 36 of positioning disk 35 by a locking spring 60, attachedto an arm projecting from housing 28. Now, in the same way as previouslydescribed in accordance with the state of the art, it would be possiblefor a connecting lever to be connected to arresting lever 57, and thisconnecting lever could have a catch which would engage in a releasablemanner in the tube at the end of the release handle. In the presentembodiment, however, a downward-pointing fork lever 62 is nonrotatablyattached to the same hub 61 as arresting lever 57, but offset in theaxial direction. A plunger 64 of a sleeve 63 extends into the open spacebetween the sidepieces of fork lever 62. The end of the plunger has atransverse head 72 projecting out toward both sides, and the sleeve isattached to the terminal area of release handle 22 in such a way that itis free to move in the longitudinal direction but is not free to rotate.The terminal area of release handle 22 begins behind transverse tube 65,which is permanently connected to release handle 22 by welding, forexample. As a result of this tube, release handle 22 is pivotablysupported in bearing brackets 66 permanently attached to the rails. Oneend of a compression spring 67, which surrounds release handle 22, isbraced against transverse tube 65; the other end of the spring acts onsleeve 63. Sleeve 63, which contains axially guided plunger 64, has alaterally projecting pin 68, which, as a result of the action ofcompression spring 67, is held against an adjusting finger 69 ofunlocking lever 24. The inside surfaces of the sidepieces of fork lever62 have radial cam sidepieces 70, with which plunger 64 can come intocontact when the rear part of release handle 22 is pivoted downward.

While seat part 10 is being held in the desired position, release handle22, unlocking lever 24, and arresting lever 57 with its fork lever 62are in the position shown in FIG. 4a. When now the longitudinal positionof the seat part of the seat is to be adjusted to a new position, handlelever 22 is pulled upward, so that its rear area pivots downward. Duringthis pivoting movement, handle lever 22 presses transverse lever 21(FIG. 8), so that the locking catches 20 of the locking device arelifted out of the row of teeth in guide rail 16; it thus becomespossible to slide movable rails 15, to which the seat is attached, inthe one or the other longitudinal direction of the vehicle.Simultaneously, however, when the rear part of handle lever 22 pivotsdownward, transverse head 72 of plunger 64 in sleeve 63 arrives atradial cam surfaces 70 and thus presses fork lever 62 forward. Thislever therefore pivots around pivot 59 in the clockwise direction, andas a result toothed segment 58 is lifted out of the locking teeth ofpositioning disk 35. This actuating position is shown in FIG. 4c. Itmust also be pointed out that, as a result of a circular path 71 onadjusting finger 69 of unlocking lever 24, which path curves around thecenter point of transverse tube 65, sleeve 63 and thus also its plunger64 retain their positions with respect to the terminal area of releasehandle 22. This is so because no change has been made to the position ofseat back 11, and therefore unlocking lever 24 has not been actuated; itthus remains in the position shown in FIGS. 4a and 4 b. When now, in theactuating position shown in FIG. 4c, the seat is slid forward or back,tension member 42 is paid out or rolled up on winding drum 32. As aresult, the cooperation of stop 45 on the drum, link block 52 restingagainst it, and counterstop 51 causes positioning disk 35 to rotatealong with the drum, which it is free to do because arresting lever 57has been swung out of position. As soon as the desired longitudinalposition of the seat has been reached and release handle 22 has been letgo, the handle swings back to its original position as shown in FIG. 4aunder the force of the spring-loaded locking catches acting in thelocking direction. At the same time, arresting lever 57 is swung back bylocking spring 60 into its locking position as shown in FIGS. 4a andFIG. 6, where it holds positioning disk 35 in a fixed position.

When now seat back 11 is flipped forward and the seat is pushed forwardout of this selected longitudinal seat position to allow more convenientaccess to the rear seat, the act of flipping back 11 forward has theeffect of pulling on Bowden cable 23. As a result, unlocking lever 24 ispivoted in the clockwise direction around pivot 26, so that, on the onehand, bent section 25 of the lever presses the rear part of releasehandle 22 down. As this is happening, pin 68 on sleeve 63 followsadjusting finger 69 as the finger pivots forward in the clockwisedirection under the force of compression spring 67, with the result thattransverse head 72 of plunger 64, occupying the gap inside fork lever62, arrives in the free space between fork lever 62 and housing 28, sothat, when the rear part of release handle 22 is pushed down by bentsection 25 for the purpose of pressing transverse lever 21 down,transverse head 72 of plunger 64 cannot come in contact with radial cams70. Arresting lever 57 therefore remains in the position in which itstoothed segment 58 is engaged with locking teeth 36 of positioning disk35. The start of this actuating process is shown in FIG. 4b. Whentransverse lever 21 is pressed down, however, it is possible, as aresult of the sliding of locking catches 20 out of the row of teeth ofthe guide rail, for the seat to be pushed forward. During this slidingmovement of the seat, link block 52 can be moved away from counterstop51 of positioning disk 35, because this stop, carried along in spiralconnecting link 50 by stop 45, is able to yield. When now the vehicleseat, which has had its back flipped forward and been pushed forward, isreturned to its original position, winding drum 32 rotates against theaction of spiral spring 40, as a result of which link block 52 iscarried along again by stop 45 until link block 52 comes to rest againstthe unchanged counterstop 51 of positioning disk 35. At this point theoriginally selected longitudinal position of the seat is reached again.

As previously mentioned, the embodiment of the object of the inventionillustrated and described above presents only an example, to which theinvention is in no way limited. On the contrary, additional designs andembodiments of the object of the invention are also possible. All of thefeatures shown in the drawing and mentioned in the description,furthermore, are essential to the invention, even if they are notexplicitly stated in the claims.

LIST OF REFERENCE NUMBERS 10 seat part 35 positioning disk 11 seat back36 locking teeth 12 arresting device 37 spiral spring 13 handle 38recess 14 pivot point 39 cutout 15 movable rail 40 spiral spring 16guide rail 41 area of reduced diameter 17 rolling element 42 tensionmember 18 rolling element 43 insertion pocket 19 locking device 44 leadretainer 20 locking catch 45 stop 21 transverse lever 46 rib 22 releasehandle 47 lock-in-position 23 Bowden cable 48 sidewall 24 unlockinglever 49 hub of 35 25 bent section 50 spiral connecting link 26 pivot 51counterstop 27 mounting plate 52 link block 28 housing 53 guide rib 29lower housing part 54 end surface of 52 30 upper housing part 55 guidefinger 31 positioning device 56 cut-out section 32 winding drum 57arresting lever 33 clip projection 58 toothed segment 34 axle 59 pivot60 locking spring 61 hub of 57 and 62 62 fork lever 63 sleeve 64 plunger65 transverse tube 66 bearing bracket 67 compression spring 68 pin on 6369 adjusting finger 70 radial cam surface 71 circular path 72 transversehead on 64

What is claimed is:
 1. A longitudinal adjusting device on a motorvehicle seat having a seat part and a seat back, wherein the seat backis connected by adjusting hardware to the seat part and is configured tobe tilted adjustably with respect to the seat part and to be flippedforward after releasing an arresting device, wherein the longitudinaladjusting device comprises: movable rails on which the seat part isfastened, the moveable rails configured to slide in guide railspermanently attached to the vehicle, wherein at least one of the movablerails has a locking device configured to releasably lock the moveablerail on the guide rail; the locking device having a positioning deviceconfigured to allow a return of the seat to a previously selectedlongitudinal position; the positioning device comprising a positioningdisc with a set of locking teeth and an arresting lever having a toothedsegment engaging the locking teeth in a selected position of the seat,wherein the arresting lever is fixedly positioned relative to themovable rail and is configured to be disengaged from the locking teethto allow rotation of the positioning disc during longitudinal adjustmentof the seat; a spring-loaded winding drum positioned coaxially to thepositioning disc and configured to allow the seat part to slide forwardby intermediate action of a tension member attached to the seat part orto the guide rail; the winding drum having a stop and the positioningdisc having a counter stop, wherein the stop is configured to limit areverse rotation of the winding drum caused by the counter stop of thepositioning disc; the positioning device comprising a spiral connectinglink; and a link block guided in the spiral connecting link and beinglocated between the stop of the winding drum and the counter stop of thepositioning disc; the link block being configured to allow rotation ofthe winding drum.
 2. The longitudinal adjusting device according toclaim 1, wherein the spiral connecting link is arranged in a sidewall ofthe positioning disc facing the winding drum and is configured to allowseveral revolutions of the winding drum relative to the position disc.3. The longitudinal adjusting device according to claim 2, wherein thelink block is a ring segment with a guide rib engaging the spiralconnecting link, wherein the spiral connecting link is a groove recessedinto the sidewall of the positioning disc.
 4. The longitudinal adjustingdevice according to claim 3, wherein the spiral connecting link has afirst end located at a short radial distance from a hub of thepositioning disc and has a second end at the counter stop, wherein thecounter stop is located radially proximal to the locking teeth of thepositioning disc, wherein the spiral connecting link has a pitch suchthat the link block passes underneath the counter stop before carryingout a last revolution when moving with a radially outwardly directedmovement component.
 5. The longitudinal adjusting device according toclaim 4, wherein the pitch of the spiral connecting link varies, whereinthe pitch at the counter stop is configured to allow the link block topass under the counter stop after completion of one revolution, whereinthe pitch is reduced thereafter to provide a spiral connecting link withas many turns as possible and to arrange the turns of the spiralconnecting link closely together in a radial direction of thepositioning disc.
 6. The longitudinal adjusting device according toclaim 4, wherein the link block has ends each provided with a guidefinger projecting away from the ends and pointing toward the hub of thepositioning disc, wherein the guide fingers form a fork and extendtangentially across an outside circumference of the hub.
 7. Thelongitudinal adjusting device according to claim 1, wherein the windingdrum has an insertion pocket configured to receive a lead retainer forthe tension member, wherein the stop of the winding drum is formed byaxial outside walls of the insertion pocket.
 8. The longitudinaladjusting device according to claim 7, wherein the counter stop of thepositioning disc projects only to such an extent from a sidewall of thepositioning disc that ribs provided on the winding drum and theinsertion pocket of the winding drum freely pass the counter stop whenthe winding drum rotates.
 9. The longitudinal adjusting device accordingto claim 1, wherein the spiral connecting link is arranged in a wall ofthe winding drum facing the positioning disc and is configured to allowseveral revolutions of the winding drum relative to the position disc.